Valve timing control apparatus

ABSTRACT

A hydraulic pressure control valve is received in a center hole of a vane rotor that is rotatable relative to a housing. A first tubular portion and a second tubular portion are fitted with each other to form an oil accumulation chamber. The oil accumulation chamber accumulates at least one of oil outputted from a gap between the housing and the vane rotor, and oil discharged from an oil passage communicated with the advancing chamber or the retarding chamber.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by referenceJapanese Patent Application No. 2012-265449 filed on Dec. 4, 2012.

TECHNICAL FIELD

The present disclosure relates to a valve timing control apparatus,which controls opening timing and closing timing of intake valves orexhaust valves of an internal combustion engine.

BACKGROUND

A known valve timing control apparatus controls opening timing andclosing timing of intake valves or exhaust valves by changing arotational phase between a crankshaft and a camshaft of an internalcombustion engine installed in, for example, a vehicle.

JP2009-515090A (corresponding to US2007/0095315A1) recites a valvetiming control apparatus that includes a hydraulic pressure controlvalve, which is installed in a vane rotor that is rotatable relative toa housing. More specifically, the hydraulic pressure control valve isinstalled in a center hole of the vane rotor, which extends in adirection of a rotational axis of the vane rotor. The hydraulic pressurecontrol valve shifts from one oil passage to another oil passage tosupply the oil, which is received from an oil pump, to advancingchambers or retarding chambers formed in the housing. In this way, thevalve timing control apparatus can advance or retard the vane rotorrelative to the housing.

However, the hydraulic pressure control valve of JP2009-515090A(corresponding to US2007/0095315A1) has an output port at a locationthat is projected from the center hole of the vane rotor to the outsideof the housing. Therefore, in the hydraulic pressure control valve, theoil of the retarding chambers is discharged from the output port to theoutside of the housing at the time of supplying the oil to the advancingchambers. Also, the oil of the advancing chambers is discharged from theoutput port to the outside of the housing at the time of supplying theoil to the retarding chambers. Therefore, it is difficult to use a drivebelt, such as a toothed belt, a flat belt or a V-belt, in a drive forcetransmission mechanism located between the crankshaft of the engine andthe housing in the valve timing control apparatus.

SUMMARY

The present disclosure is made in view of the above points. According tothe present disclosure, there is provided a valve timing controlapparatus that controls opening timing and closing timing of one of anintake valve and an exhaust valve of an internal combustion engine,which is opened and closed by a driven-side shaft of the internalcombustion engine, through changing of a rotational phase between adriving-side shaft of the internal combustion engine and the driven-sideshaft. The valve timing control apparatus includes a housing, a vanerotor, a hydraulic pressure control valve, a solenoid, a first tubularportion and a second tubular portion. The housing is rotatableintegrally with the driving-side shaft. The vane rotor is rotatablerelative to the housing according to a hydraulic pressure of anadvancing chamber formed in the housing and a hydraulic pressure of aretarding chamber formed in the housing. The vane rotor is fixed to thedriven-side shaft. The hydraulic pressure control valve includes asleeve and a spool. The sleeve is received in a center hole of the vanerotor, which extends in a direction of a rotational axis of the vanerotor. The spool is received in an inside of the sleeve and isconfigured to reciprocate along the sleeve. The hydraulic pressurecontrol valve changes a hydraulic pressure, which is supplied to or isdischarged from the advancing chamber, and a hydraulic pressure, whichis supplied to or is discharged from the retarding chamber, throughmovement of the spool. The solenoid includes a solenoid main body and apress pin. The solenoid main body is opposed to the housing. The presspin projects from the solenoid main body and is configured to press thespool of the hydraulic pressure control valve. The solenoid controls thechanging of the hydraulic pressures at the hydraulic pressure controlvalve. The first tubular portion extends from the housing toward thesolenoid. The second tubular portion extends from the solenoid main bodyor an installation member, to which the solenoid main body is installed,toward the housing and is fitted to the first tubular portion. Thesecond tubular portion cooperates with the first tubular portion to forman oil accumulation chamber that is configured to accumulate at leastone of oil outputted from a gap between the housing and the vane rotor,and oil discharged from an oil passage communicated with the advancingchamber or the retarding chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a longitudinal cross sectional view of a valve timing controlapparatus according to a first embodiment of the present disclosure;

FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1;

FIG. 3 is a schematic view showing a structure of a drive forcetransmission mechanism, in which the valve timing control apparatus ofthe first embodiment is used;

FIG. 4 is a partial enlarged cross-sectional view of a portion of FIG.1;

FIG. 5 is a longitudinal cross sectional view of a valve timing controlapparatus according to a second embodiment of the present disclosure;

FIG. 6 is a longitudinal cross sectional view of a valve timing controlapparatus according to a third embodiment of the present disclosure;

FIG. 7 is a longitudinal cross sectional view of a valve timing controlapparatus according to a fourth embodiment of the present disclosure;

FIG. 8 is a cross sectional view taken along line VIII-VIII in FIG. 7;and

FIG. 9 is an enlarged partial cross-sectional view of a main featureshown in

FIG. 7.

DETAILED DESCRIPTION

Various embodiments of the present disclosure will be described withreference to the accompanying drawings.

First Embodiment

FIGS. 1 to 4 show a first embodiment of the present disclosure. A valvetiming control apparatus 1 of the present embodiment is used in a driveforce transmission mechanism of an internal combustion engine 2 of avehicle (e.g., an automobile) shown in FIG. 3. The drive forcetransmission mechanism is placed in an inside of an engine cover 3. Inthe drive force transmission mechanism, a drive belt 17 is would arounda pulley 12, a pulley 15 and a pulley 16. The pulley 12 is fixed to acrankshaft 11, which serves as a driving-side shaft of the engine 2. Thepulley 15 is fixed to a camshaft 13, which serves as a driven-sideshaft, and the pulley 16 is fixed to a camshaft 14, which serves as adriven-side shaft. A torque of the crankshaft 11 is transmitted to thecamshafts 13, 14 through the drive belt 17. The camshaft 13 drivesintake valves 18 to open and close the intake valves 18. The camshaft 14drives exhaust valves 19 to open and close the exhaust valves 19. In thevalve timing control apparatus 1 of the first embodiment, the pulley 15is connected to the drive belt 17, and a vane rotor 30 is connected tothe camshaft 13. The crankshaft 11 and the camshaft 13 are rotated suchthat a predetermined phase difference is formed between the crankshaft11 and the camshaft 13, and thereby the opening timing and the closingtiming of the intake valves 18 are controlled.

An arrow shown in FIG. 3 indicates a rotational direction of the drivebelt 17.

As shown in FIGS. 1 and 2, the valve timing control apparatus 1 includesa housing 20, the vane rotor 30, a hydraulic pressure control valve 40and a solenoid 50.

The housing 20 includes a front plate 21, a rear plate 22, a tubularportion 23 and shoes 24-26. The front plate 21, the rear plate 22 andthe tubular portion 23 are held together by bolts 27.

The front plate 21 is configured into an annular form (a ring form). Afirst tubular portion 91, which is configured into a cylindrical tubularform, axially extends from a radially inner end of the front plate 21 onan axial side where the solenoid 50 is located. The front plate 21 isformed integrally with the first tubular portion 91.

The rear plate 22 is configured into an annular form and is axiallyopposed to the front plate 21 such that the vane rotor 30 is axiallyheld between the rear plate 22 and the front plate 21. The rear plate 22has a rear hole 28, into which a rear bushing 38 of the vane rotor 30 isreceived.

The tubular portion 23 and the shoes 24-26 are integrally formed and areheld between the front plate 21 and the rear plate 22 in the axialdirection. The shoes 24-26 are arranged one after another atpredetermined intervals in a circumferential direction of the tubularportion 23 and extend radially inward from the tubular portion 23. Ahydraulic pressure chamber 35, which has a fan-shaped cross-section, isformed between each circumferentially adjacent two of the shoes 24-26.

The drive belt 17 is wound around the pulley 15, which is formed in theouter peripheral part of the tubular portion 23, so that the housing 20is rotated integrally with the crankshaft 11.

The vane rotor 30 is rotatable relative to the housing 20. The vanerotor 30 includes a rotor (also referred to as a boss) 31, a rearbushing 38 and a plurality of vanes 32-34. The rotor 31 is configuredinto a cylindrical tubular form. The rear bushing 38 axially extendsfrom the rotor 31. The vanes 32-34 radially outwardly extend from therotor 31.

Each outer peripheral wall portion of the rotor 31, which iscircumferentially placed between corresponding adjacent two of the vanes32-34, is fluid-tightly slidable along an inner peripheral wall portionof a corresponding one of the shoes 24-26 of the housing 20. The rotor31 has a center hole 36, which extends in a direction of a rotationalaxis of the rotor 31 at a center of the rotor 31. The center hole 36axially receives a hydraulic pressure control valve 40.

The rear bushing 38 is configured into a tubular form and extends fromthe rotor 31 into the rear hole 28 of the rear plate 22. The rearbushing 38 and the camshaft 13 are fluid-tightly fixed with each other.The rear bushing 38 is rotatable relative to the rear hole 28 of therear plate 22.

Each of the vanes 32-34 partitions a corresponding one of the hydraulicpressure chambers 35 of the housing 20 into an advancing chamber 60-62and a retarding chamber 63-65. The hydraulic pressure is supplied to oris discharged from the advancing chambers 60-62 through advancing oilpassages 70-72. Also, the hydraulic pressure is supplied to or isdischarged from the retarding chambers 63-65 through retarding oilpassages 73-75.

A seal member 39 is installed to an outer peripheral wall portion ofeach of the vanes 32-34. The seal member 39 limits the flow of the oilbetween the corresponding advancing chamber 60-62 and the correspondingretarding chamber 63-65, which are located on one circumferential sideand the other circumferential side, respectively, of the vane 32-34having the seal member 39. The vane rotor 30 is rotatable relative tothe housing 20 according to the hydraulic pressure of the advancingchambers 60-62 and the hydraulic pressure of the retarding chambers63-65.

A counterclockwise arrow and a clockwise arrow shown in FIG. 2 indicatethe advancing direction and the retarding direction, respectively, ofthe vane rotor 30 relative to the housing 20.

A stopper piston 80 is received in a hole of the vane rotor 30 in amanner that enables axial reciprocation of the stopper piston 80. A ring82 is received in a recess 81 of the rear plate 22, and the stopperpiston 80 can be fitted into or removed from the ring 82 upon thereciprocation of the stopper piston 80. The stopper piston 80 can befitted into the ring 82 by an urging force of a spring 83 when the vanerotor 30 is placed in a most retarded position relative to the housing20.

A first pressure chamber 84 and a second pressure chamber 85 are formedaround the stopper piston 80. One of the first pressure chamber 84 andthe second pressure chamber 85 is communicated with the retardingchambers 63-65, and the other one of the first pressure chamber 84 andthe second pressure chamber 85 is communicated with the advancingchambers 60-62.

When a sum of the hydraulic pressure of the first pressure chamber 84applied to the stopper piston 80 and the hydraulic pressure of thesecond pressure chamber 85 applied to the stopper piston 80 becomeslarger than the urging force of the spring 83, the stopper piston 80 isremoved from the ring 82.

The hydraulic pressure control valve 40 includes a sleeve 41 and a spool42. The sleeve 41 is configured into a tubular bolt form. The spool 42is received in the sleeve 41.

The sleeve 41 extends through the center hole 36 of the vane rotor 30and is threadably engaged with a female-thread of the camshaft 13, and ahead 43 of the sleeve 41 contacts the vane rotor 30. In this way, thecamshaft 13, the vane rotor 30 and the sleeve 41 are fixed together.

As shown in FIGS. 1 and 4, the sleeve 41 has a first port 401, a secondport 402 and a third port 403, which radially extend through an outerperipheral wall of the sleeve 41 and are axially arranged one afteranother in this order from the head 43 side of the sleeve 41.Furthermore, the sleeve 41 has a slide chamber 44 and an axial passage45. The slide chamber 44 axially receives the spool 42. The axialpassage 45 communicates between the slide chamber 44 and an oildischarge passage (also referred to as a first oil discharge passage)131 of the camshaft 13.

The first port 401 is communicated with the advancing oil passages 70-72of the vane rotor 30.

The second port 402 is communicated with a supply passage 133 of thevane rotor 30. The supply passage 133 of the vane rotor 30 iscommunicated with a hydraulic pressure supply passage 130 of thecamshaft 13. Thereby, the oil, which is pumped by an oil pump 5 from anoil pan 4 of the vehicle, is supplied to the second port 402 through thesupply passage 133 of the vane rotor 30 and the hydraulic pressuresupply passage 130 of the camshaft 13.

The third port 403 is communicated with the retarding oil passages 73-75of the vane rotor 30.

The spool 42 is received in the slide chamber 44 of the sleeve 41 in amanner that enables reciprocation of the spool 42 in the axialdirection. A stopper ring 431, which is installed to the head 43 of thesleeve 41, limits removal of the spool 42 from the slide chamber 44 ofthe sleeve 41.

A spring 46 is placed between the spool 42 and an inner wall of theslide chamber 44 of the sleeve 41. The spring 46 urges the spool 42toward the stopper ring 431.

The spool 42 has an inside passage 47, which is formed in the inside ofthe spool 42. The inside passage 47 is communicated with the slidechamber 44 of the sleeve 41.

The spool 42 has a front groove and hole portion 421, a middle grooveportion 422 and a rear groove and hole portion 423, which are formed inthe outer peripheral wall of the spool 42 and are arranged in this orderfrom the front side to the rear side in the axial direction.

A first land 424 is formed between the front groove and hole portion 421and the middle groove portion 422 in the outer peripheral wall of thespool 42. A second land 425 is formed between the middle groove portion422 and the rear groove and hole portion 423 in the outer peripheralwall of the spool 42.

The first land 424 enables and disables communication between the firstport 401 and the front groove and hole portion 421. The first land 424also enables and disables communication between the first port 401 andthe middle groove portion 422.

The second land 425 enables and disables communication between the thirdport 403 and the middle groove portion 422. The second land 425 alsoenables and disables communication between the third port 403 and therear groove and hole portion 423.

The front groove and hole portion 421 is communicated with an oilaccumulation chamber (also referred to as an oil well or an oil pool) 90and the inside passage 47. In this way, the oil accumulation chamber 90is communicated with the oil discharge passage 131 of the camshaft 13through the front groove and hole portion 421, the inside passage 47,the slide chamber 44 and the axial passage 45.

The front groove and hole portion 421, the inside passage 47, the slidechamber 44 and the axial passage 45 form a communication passage 100that communicates between the oil accumulation chamber 90 and the oildischarge passage 131.

The middle groove portion 422 communicates between the first port 401and the second port 402 or communicates between the second port 402 andthe third port 403.

The rear groove and hole portion 423 is communicated with the insidepassage 47.

The solenoid 50 is installed to an installation hole 6 of the enginecover 3 with bolts 7. The engine cover 3 serves as an installationmember, to which a solenoid main body 51 of the solenoid 50 isinstalled. Besides the solenoid main body 51, the solenoid 50 furtherincludes a press pin 52. The press pin 52 projects from the solenoidmain body 51. A small gap 10 is formed between the solenoid main body 51and an inner peripheral wall 6 a of the installation hole 6. This gap 10is used to coaxially align the solenoid 50 and the housing 20 with eachother, i.e., to enable adjustment of the alignment between a rotationalaxis Oa of the housing 20 and a central axis Ob of the press pin 52.

The solenoid main body 51 is operated through energization from anundepicted electronic control unit (ECU) to axially drive the press pin52. The press pin 52 can press the spool 42 toward the spring 46.

When the spool 42 is moved, the hydraulic pressure, which is supplied tothe advancing chambers 60-62 and the hydraulic pressure, which issupplied to the retarding chambers 63-65, are controlled. The ECU drivesthe solenoid 50 to coincide the rotational phase of the vane rotor 30relative to the housing 20 with a target rotational phase.

A second tubular portion 92, which is configured into a cylindricaltubular form, extends from the solenoid main body 51 toward the housing20. The solenoid main body 51 and the second tubular portion 92 areintegrally formed.

The second tubular portion 92 is fitted to an outer peripheral wallsection (also referred to as a radially outer side section) of the firsttubular portion 91. Thereby, the oil accumulation chamber 90 is formedin the inside of the first tubular portion 91 and the second tubularportion 92. The oil accumulation chamber 90 accumulates, i.e., storesthe oil, which is discharged from a gap(s), such as a gap 110, formedbetween the housing 20 and the vane rotor 30, and/or the oil, which isdischarged from the advancing oil passages 70-72 or the retarding oilpassages 73-75.

The first tubular portion 91 includes a first guiding part 93, which isconfigured into a cylindrical tubular form. An outer peripheral wallsection (also referred to as a radially outer side section) 93 a of thefirst guiding part 93, which is formed as a part of the outer peripheralwall of the first tubular portion 91, slidably contacts the secondtubular portion 92. The second tubular portion 92 includes a secondguiding part 94, which is configured into a cylindrical tubular form. Aninner peripheral wall section (also referred to as a radially inner sidesection) 94 b of the second guiding part 94, which is formed as a partof the inner peripheral wall of the second tubular portion 92, slidablycontacts the first tubular portion 91, more specifically, the outerperipheral wall section 93 a of the first guiding part 93. When thefirst guiding part 93 and the second guiding part 94 slidably contactwith each other, the rotational axis Oa of the housing 20 and thecentral axial Ob of the press pin 52 of the solenoid 50 aresubstantially placed along a common axis (a central axis) O to coaxiallyalign the housing 20 and the solenoid 50 with each other. In this way,the press pin 52 of the solenoid 50 can reliably press the spool 42,which is placed along the rotational axis Oa of the housing 20.

The second tubular portion 92 includes a stepped part 95, which has aninner diameter that is larger than an inner diameter of the secondguiding part 94. A seal member 96 is made of, for example, a resinmaterial or a rubber material and is configured into an annular form (aring form). The seal member 96 is fixed to the stepped part 95 of thesecond tubular portion 92 by, for example, press-fitting. The sealmember 96 has a seal surface 97, which fluid-tightly and slidablycontacts the outer peripheral wall of the first tubular portion 91. Theseal member 96 includes a spring 98, which is configured into an annularform and is placed in the inside of the seal member 96. The spring 98urges the seal surface 97 of the seal member 96 in a radially innerdirection to improve the fluid-tightness between the seal surface 97 andthe outer peripheral wall section of the first tubular portion 91.

Next, the operation of the valve timing control apparatus 1 will bedescribed.

(Engine Start Time)

As shown in FIGS. 1 and 2, in a state where the engine 2 is stopped, thestopper piston 80 is receive in the inside of the ring 82, and the vanerotor 30 is held in the most retarded position relative to the housing20. In a state immediately after starting of the engine 2, thesufficient amount of oil is not supplied to the retarding chambers63-65, the advancing chambers 60-62, the first pressure chamber 84 andthe second pressure chamber 85 (these chambers also being referred to ashydraulic chambers), so that the stopper piston 80 is maintained in thereceived state, in which the stopper piston 80 is received in the insideof the ring 82. Therefore, it is possible to limit generation of ahitting sound (hammering sound), which would be generated between thehousing 20 and the vane rotor 30 due to a torque change applied to thecamshaft 13.

(After Engine Start)

After the start of the engine 2, when the sufficient amount of oil issupplied to each hydraulic chamber from the oil pump 5, the stopperpiston 80 is removed from the ring 82 against the urging force of thespring 83 by the hydraulic pressure of the first pressure chamber 84 andthe hydraulic pressure of the second pressure chamber 85. Thereby, therotation of the vane rotor 30 relative to the housing 20 is enabled.

(Time of Advancing Operation)

In the advancing operation of the valve timing control apparatus 1, thesolenoid 50 receives a corresponding command from the ECU and removes(or releases) the press force of the press pin 52, which presses thespool 42 of the hydraulic pressure control valve 40 toward the spring46. In this way, the oil is supplied from the hydraulic pressure supplypassage 130 to the advancing chambers 60-62 through the second port 402,the first port 401 and the advancing oil passages 70-72. In contrast,the oil of the retarding chambers 63-65 is discharged to the insidepassage 47 through the retarding oil passages 73-75, the third port 403,and the rear groove and hole portion 423. In this way, the hydraulicpressure of the advancing chambers 60-62 is applied to the vanes 32-34,and thereby the vane rotor 30 is rotated relative to the housing 20 inthe advancing direction.

(Time of Retarding Operation)

In the retarding operation of the valve timing control apparatus 1, thesolenoid 50 receives a corresponding command from the ECU and drives thepress pin 52 to press the spool 42 of the hydraulic pressure controlvalve 40 toward the spring 46. In this way, the oil is supplied from thehydraulic pressure supply passage 130 to the retarding chambers 63-65through the second port 402, the third port 403 and the retarding oilpassages 73-75. In contrast, the oil of the advancing chambers 60-62 isdischarged to the inside passage 47 or the oil accumulation chamber 90through the advancing oil passages 70-72, the first port 401 and thefront groove and hole portion 421. In this way, the hydraulic pressureof the retarding chambers 63-65 is applied to the vanes 32-34, andthereby the vane rotor 30 is rotated relative to the housing 20 in theretarding direction.

(Intermediate Holding Operation)

When the vane rotor 30 reaches the target phase, the hydraulic pressurecontrol valve 40 limits the discharge of the hydraulic pressure from theretarding chambers 63-65 and the advancing chambers 60-62 to the oil pan4. At this time, the minute amount of hydraulic pressure is suppliedfrom the hydraulic pressure supply passage 130 to the retarding chambers63-65 and the advancing chambers 60-62 through the retarding oilpassages 73-75 and the advancing oil passages 70-72. Thereby, the vanerotor 30 is held in the target phase.

(Time of Engine Stop)

When a command, which stops the engine 2, is outputted during theoperating period of the valve timing control apparatus 1, the vane rotor30 is rotated relative to the housing 20 in the retarding directionthrough the operation, which is similar to the retarding operationdiscussed above, and the vane rotor 30 is stopped in the most retardedposition. In this state, when the operation of the oil pump 5 is stoppedto cause a reduction in the pressure of the first pressure chamber 84and a reduction in the pressure of the second pressure chamber 85, thestopper piston 80 is urged into the inside of the ring 82 by the urgingforce of the spring 83. In this state, the engine 2 is stopped.

Now, the advantages of the first embodiment will be described.

(1) In the first embodiment, the first tubular portion 91, which extendsfrom the housing 20, and the second tubular portion 92, which extendsfrom the solenoid main body 51, are fitted together to form the oilaccumulation chamber 90. In this way, a portion of the oil, which isdischarged from the gap(s) between the housing 20 and the vane rotor 30,or the oil, which is discharge from the advancing oil passages 70-72 orthe retarding oil passages 73-75, is accumulated in the oil accumulationchamber 90. Thereby, the leakage of the oil to the outside of thehousing 20 can be limited in the valve timing control apparatus 1. Thus,it is possible to use the drive belt (e.g., a toothed belt, a flat beltor a V-belt) in the drive force transmission mechanism between thehousing 20 and the driving-side shaft (i.e., the crankshaft 11) in thevalve timing control apparatus 1.

(2) In the first embodiment, the first guiding part 93 of the firsttubular portion 91 and the second guiding part 94 of the second tubularportion 92 slidably contact with each other, so that the rotational axisOa of the housing 20 and the central axis Ob of the press pin 52 of thesolenoid 50 are substantially coaxially aligned along the common axis O.In this way, the press pin 52 can reliably contact the center (thecentral axis) of the spool 42, so that the hydraulic pressure controlvalve 40 can be reliably controlled by the solenoid 50.

(3) In the first embodiment, the seal member 96 is placed between thefirst tubular portion 91 and the second tubular portion 92. The firsttubular portion 91 and the second tubular portion 92 are substantiallycoaxially arranged through the slide contact between the first guidingpart 93 of the first tubular portion 91 and the second guiding part 94of the second tubular portion 92. In this way, the plate thickness (theradial thickness) of the seal member 96 becomes generally uniform alongthe entire circumferential extent of the seal member 96, so that theleakage of the oil from the oil accumulation chamber 90 can be reliablylimited.

(4) In the first embodiment, the oil discharge passage 131 of thecamshaft 13 and the oil accumulation chamber 90 are communicated witheach other through the front groove and hole portion 421, the insidepassage 47, the slide chamber 44 and the axial passage 45 of thehydraulic pressure control valve 40. In this way, the oil, which isaccumulated in the oil accumulation chamber 90, can be discharged to theoil discharge passage 131 of the camshaft 13. Thus, the leakage of theoil from the oil accumulation chamber 90 can be reliable limited bylimiting the pressure increase of the oil accumulation chamber 90.

(5) In the first embodiment, the gap 10, which enables the coaxialalignment, is provided between the solenoid main body 51 and the innerperipheral wall 6 a of the installation hole 6 of the engine cover 3, towhich the solenoid main body 51 is installed. In this way, the housing20 and the solenoid 50 can be reliably coaxially aligned with each otherthrough the fitting between the first tubular portion 91 and the secondtubular portion 92.

Second Embodiment

FIG. 5 shows a second embodiment of the present disclosure. In thefollowing embodiments, the components, which are similar to those of thefirst embodiment, will be indicated by the same reference numerals andwill not be described again for the sake of simplicity.

In the second embodiment, the first tubular portion 91, which extendsfrom the housing 20, is fitted to the outer peripheral wall (theradially outer side section) of the second tubular portion 92, whichextends from the solenoid main body 51. Specifically, an innerperipheral wall section (also referred to as a radially inner sidesection) 93 b of the first guiding part 93, which is formed as a part ofthe inner peripheral wall of the first tubular portion 91, slidablycontacts an outer peripheral wall section (also referred to as aradially outer side section) 94 b of the second guiding part 94, whichis formed as a part of the outer peripheral wall of the second tubularportion 92. Thereby, the housing 20 is substantially coaxially alignedwith the solenoid 50.

The second tubular portion 92 includes the stepped part 95, which hasthe inner diameter that is smaller than the inner diameter of the secondguiding part 94. The seal member 96 is fixed to the inner peripheralwall of the first tubular portion 91, which is opposed to the steppedpart 95, by, for example, press-fitting. The seal surface 97 of the sealmember 96 fluid-tightly and slidably contacts the stepped part 95 of thesecond tubular portion 92. In this way, the leakage of the oil from theoil accumulation chamber 90 is limited.

According to the second embodiment, the advantages, which are similar tothose of the first embodiment, are achieved.

Third Embodiment

FIG. 6 shows a third embodiment of the present disclosure, which is amodification of the first embodiment. In the third embodiment, thesecond tubular portion 92 is formed separately from the solenoid mainbody 51 and is installed to the engine cover 3. The inner peripheralwall of the second tubular portion 92 contacts a cylindrical tubularportion 53 of the solenoid main body 51. The cylindrical tubular portion53 and the press pin 52 are substantially coaxial with each other.Thereby, the second tubular portion 92 and the solenoid 50 aresubstantially coaxially installed.

The housing 20 and the second tubular portion 92 are held substantiallycoaxial with each other through the slide contact between the firstguiding part 93 of the first tubular portion 91 and the second guidingpart 94 of the second tubular portion 92. Since the second tubularportion 92 and the solenoid 50 are substantially coaxial with eachother, the housing 20 and the solenoid 50 are substantially coaxial witheach other. In this way, the press pin 52 of the solenoid 50 canreliably press the spool 42 of the hydraulic pressure control valve 40,which is placed along the rotational axis Oa of the housing 20.

According to the third embodiment, the advantages, which are similar tothose of the first and second embodiments, are achieved.

Fourth Embodiment

FIGS. 7 to 9 show a fourth embodiment of the present disclosure. Thevalve timing control apparatus of the fourth embodiment adjusts theopening timing and closing timing of the exhaust valves 19.

In the housing 20, a seal member 29 is held between the front plate 21,which is located on the front side of the seal member 29, and thetubular portion 23 and the shoes 24, 26, which are located on the rearside of the seal member 29. Furthermore, a seal member 291 is heldbetween the rear plate 22, which is located on the rear side of the sealmember 291, and the tubular portion 23 and the shoes 24-26, which arelocated on the front side of the seal member 291. In this way, leakageof the oil to the outside of the housing 20 can be limited.

The rear plate 22 includes an annular portion 221 and a cylindricaltubular portion 222. The annular portion 221 is configured into anannular form (a ring form). The cylindrical tubular portion 222 axiallyextends from a radially inner part (an inner peripheral edge) of theannular portion 221 toward an engine head 8.

The cylindrical tubular portion 222 is fitted into a recess 9 of theengine head 8. The cylindrical tubular portion 222 is installed to theengine head 8 in a rotatable manner.

A seal member 99 is installed between an outer peripheral wall of thecylindrical tubular portion 222 of the rear plate 22 and an innerperipheral wall of the recess 9 of the engine head 8. The seal member 99limits leakage of the oil thought the gap(s) between the cylindricaltubular portion 222 of the rear plate 22 and the engine head 8.

The vane rotor 30 includes a second communication passage 37, whichextends through the vane rotor 30 in the direction of the rotationalaxis. One end of the second communication passage 37 of the vane rotor30 opens to an inside of the first tubular portion 91, and the other endof the second communication passage 37 opens to an inside of thecylindrical tubular portion 222 of the rear plate 22. The space in theinside of the cylindrical tubular portion 222 of the rear plate 22 iscommunicated with a second oil discharge passage 132 of the engine head8. Therefore, the oil accumulation chamber 90 is communicated with thesecond oil discharge passage 132 of the engine head 8 through the secondcommunication passage 37 of the vane rotor 30 and the space in theinside of the cylindrical tubular portion 222 of the rear plate 22.

An annular member 48 is installed between the head 43 of the sleeve 41and the vane rotor 30. A return spring 49 is installed at an outside ofthe head 43 of the sleeve 41. One end portion of the return spring 49 isengaged with a groove 481 of the annular member 48, and the other endportion of the return spring 49 is engaged with a groove 911 formed inthe inner peripheral wall of the first tubular portion 91. The returnspring 49 urges the vane rotor 30 in the advancing direction.

The spool 42 has a front groove and hole portion 421, a middle grooveportion 422 and a rear groove and hole portion 423, which are formed inthe outer peripheral wall of the spool 42 and are arranged in this orderfrom the front side to the rear side in the axial direction.

The front groove and hole portion 421 is communicated with the insidepassage 47 and is not opened to the oil accumulation chamber 90.

The middle groove portion 422 and the rear groove and hole portion 423are similar to the middle groove portion 422 and the rear groove andhole portion 423 of the first to third embodiments.

The second tubular portion 92, which extends from the solenoid main body51 toward the housing 20, is fitted to the first tubular portion 91 toform the oil accumulation chamber 90, and this oil accumulation chamber90 accumulates the oil, which is leaked from the gap(s) between thehousing 20 and the vane rotor 30. In the fourth embodiment, the oil isnot directly discharged from the advancing oil passages 70-72 or theretarding oil passages 73-75 into the oil accumulation chamber 90.

Next, the operation of the valve timing control apparatus of the fourthembodiment will be described.

(Engine Start Time)

As shown in FIGS. 7 and 8, in the state where the engine 2 is stopped,the stopper piston 80 is receive in the inside of the ring 82, and thevane rotor 30 is held in the most retarded position relative to thehousing 20.

(After Engine Start)

After the start of the engine 2, when the sufficient amount of oil issupplied to each corresponding hydraulic chamber from the oil pump 5,the stopper piston 80 is removed from the ring 82. Thereby, the rotationof the vane rotor 30 relative to the housing 20 is enabled.

(Time of Retarding Operation)

In the retarding operation of the valve timing control apparatus, thesolenoid 50 receives the corresponding command from the ECU and drivesthe press pin 52 to press the spool 42 of the hydraulic pressure controlvalve 40 toward the spring 46. In this way, the oil is supplied from thehydraulic pressure supply passage 130 to the retarding chambers 63-65through the second port 402, the third port 403 and the retarding oilpassages 73-75. In contrast, the oil of the advancing chambers 60-62 isdischarged to the inside passage 47 through the advancing oil passages70-72, the first port 401 and the front groove and hole portion 421. Inthis way, the hydraulic pressure of the retarding chambers 63-65 isapplied to the vanes 32-34, and thereby the vane rotor 30 is rotatedrelative to the housing 20 in the retarding direction.

(Time of Advancing Operation)

In the advancing operation of the valve timing control apparatus, thesolenoid 50 receives the corresponding command from the ECU and removesthe press force, which drives the press pin 52, so that the press forceof the press pin 52, which presses the spool 42 of the hydraulicpressure control valve 40 toward the spring 46, is removed. In this way,the oil is supplied from the hydraulic pressure supply passage 130 tothe advancing chambers 60-62 through the second port 402, the first port401 and the advancing oil passages 70-72. In contrast, the oil of theretarding chambers 63-65 is discharged to the inside passage 47 throughthe retarding oil passages 73-75, the third port 403, and the reargroove and hole portion 423. In this way, the hydraulic pressure of theadvancing chambers 60-62 is applied to the vanes 32-34, and thereby thevane rotor 30 is rotated relative to the housing 20 in the advancingdirection.

(Time of Engine Stop)

When the command, which stops the engine 2, is outputted during theoperating period of the valve timing control apparatus, the vane rotor30 is rotated relative to the housing 20 in the retarding directionthrough the operation, which is similar to the retarding operationdiscussed above, and the vane rotor 30 is stopped in the most retardedposition. In this state, when the operation of the oil pump 5 is stoppedto cause a reduction in the pressure of the first pressure chamber 84and a reduction in the pressure of the second pressure chamber 85, thestopper piston 80 is urged into the inside of the ring 82 by the urgingforce of the spring 83. In this state, the engine 2 is stopped.

Now, the advantages of the fourth embodiment will be described.

(1) In the fourth embodiment, the vane rotor 30 has the secondcommunication passage 37 that communicates between the second oildischarge passage 132, which is formed in the engine head 8, and the oilaccumulation chamber 90. Thereby, the oil, which is accumulated in theoil accumulation chamber 90, can be outputted to the second oildischarge passage 132 of the engine head 8 through the secondcommunication passage 37. Thus, the leakage of the oil from the oilaccumulation chamber 90 can be reliable limited.

(2) In the fourth embodiment, the oil, which is discharged from theadvancing oil passages 70-72 or the retarding oil passages 73-75, flowsfrom the first port 401 or the third port 403 of the sleeve 41 to theoil discharge passage 131 of the camshaft 13 through the inside passage47 in the spool 42 without passing through the oil accumulation chamber90.

In this way, the hydraulic pressure, which is applied from the oilaccumulation chamber 90 to the vane rotor 30, is reduced, and therebythe frictional force between the vane rotor 30 and the housing 20 isreduced.

Furthermore, since the oil pressure, which is applied from the oilaccumulation chamber 90 to the solenoid 50, is reduced, the reliabilityof the solenoid 50 can be improved.

Furthermore, the pressure loss of the oil, which flows from theadvancing chambers 60-62 or the retarding chambers 63-65 to the oildischarge passage 131, is reduced.

Thus, the response of the phase control operation of the vane rotor 30relative to the housing 20 can be improved.

Now, modifications of the above embodiments will be described.

In the above embodiments, the oil passages, which are communicated withthe first port 401 of the hydraulic pressure control valve 40, areadvancing oil passages 70-72. Furthermore, the oil passages, which arecommunicated with the third port 403 of the hydraulic pressure controlvalve 40, are the retarding oil passages 73-75. Alternatively, in amodification of the above embodiments, the oil passages, which arecommunicated with the first port 401 of the hydraulic pressure controlvalve 40, may be retarding oil passages 73-75, and the oil passages,which are communicated with the third port 403 of the hydraulic pressurecontrol valve 40, may be the advancing oil passages 70-72.

The present disclosure is not limited to the above embodiments, and theabove embodiments may be further modified according to the principle ofthe present disclosure. For example, any one or more of the abovefeatures of any one of the embodiments may be combined with any one ormore of the above features of any other one or more of the aboveembodiments.

What is claimed is:
 1. A valve timing control apparatus that controlsopening timing and closing timing of one of an intake valve and anexhaust valve of an internal combustion engine, which is opened andclosed by a driven-side shaft of the internal combustion engine, throughchanging of a rotational phase between a driving-side shaft of theinternal combustion engine and the driven-side shaft, the valve timingcontrol apparatus comprising: a housing that is rotatable integrallywith the driving-side shaft; a vane rotor that is rotatable relative tothe housing according to a hydraulic pressure of an advancing chamberformed in the housing and a hydraulic pressure of a retarding chamberformed in the housing, wherein the vane rotor is fixed to thedriven-side shaft; a hydraulic pressure control valve that includes: asleeve that is received in a center hole of the vane rotor, whichextends in a direction of a rotational axis of the vane rotor; and aspool that is received in an inside of the sleeve and is configured toreciprocate along the sleeve, wherein the hydraulic pressure controlvalve changes a hydraulic pressure, which is supplied to or isdischarged from the advancing chamber, and a hydraulic pressure, whichis supplied to or is discharged from the retarding chamber, throughmovement of the spool; a solenoid that includes: a solenoid main bodythat is opposed to the housing; and a press pin that projects from thesolenoid main body and is configured to press the spool of the hydraulicpressure control valve, wherein the solenoid controls the changing ofthe hydraulic pressures at the hydraulic pressure control valve; a firsttubular portion that extends from the housing toward the solenoid; and asecond tubular portion that extends from the solenoid main body or aninstallation member, to which the solenoid main body is installed,toward the housing and is fitted to the first tubular portion, whereinthe second tubular portion cooperates with the first tubular portion toform an oil accumulation chamber that is configured to accumulate atleast one of: oil outputted from a gap between the housing and the vanerotor; and oil discharged from an oil passage communicated with theadvancing chamber or the retarding chamber.
 2. The valve timing controlapparatus according to claim 1, wherein: the first tubular portionincludes a first guiding part that is configured into a cylindricaltubular form and slidably contacts the second tubular portion; thesecond tubular portion includes a second guiding part that is configuredinto a cylindrical tubular form and slidably contacts the first tubularportion; and the first guiding part and the second guiding part slidablycontact with each other to substantially place a rotational axis of thehousing and a central axis of the press pin along a common axis.
 3. Thevalve timing control apparatus according to claim 1, wherein the secondguiding part slidably contacts one of a radially outer side section anda radially inner side section of the first guiding part.
 4. The valvetiming control apparatus according to claim 1, wherein a seal member,which is configured into an annular form, is placed between the firsttubular portion and the second tubular portion to limit leakage of oilfrom the oil accumulation chamber.
 5. The valve timing control apparatusaccording to claim 1, wherein the solenoid main body and the secondtubular portion are integrally formed.
 6. The valve timing controlapparatus according to claim 1, wherein a gap is formed between thesolenoid main body and an inner peripheral wall of an installation holeof the installation member to enable adjustment of alignment between arotational axis of the housing and a central axis of the press pin. 7.The valve timing control apparatus according to claim 1, wherein thehydraulic pressure control valve includes a communication passage thatcommunicates between the oil accumulation chamber and an oil dischargepassage that is formed in the driven-side shaft.
 8. The valve timingcontrol apparatus according to claim 1, wherein the vane rotor includesa second communication passage that communicates between the oilaccumulation chamber and a second oil discharge passage, which is formedin an engine head of the internal combustion engine fluid-tightly fittedto the housing.
 9. The valve timing control apparatus according to claim8, wherein the oil, which is discharged from the advancing chamber, andthe oil, which is discharged from the retarding chamber, are conductedto an oil discharge passage, which is formed in the driven-side shaft,through a port of the sleeve, a groove and hole portion of the spool andan inside passage of the spool without passing through the oilaccumulation chamber.